White matter, cognition and psychotic-like experiences in UK Biobank.

BACKGROUND: Psychotic-like experiences (PLEs) are risk factors for the development of psychiatric conditions like schizophrenia, particularly if associated with distress. As PLEs have been related to alterations in both white matter and cognition, we investigated whether cognition (g-factor and processing speed) mediates the relationship between white matter and PLEs. METHODS: We investigated two independent samples (6170 and 19 891) from the UK Biobank, through path analysis. For both samples, measures of whole-brain fractional anisotropy (gFA) and mean diffusivity (gMD), as indications of white matter microstructure, were derived from probabilistic tractography. For the smaller sample, variables whole-brain white matter network efficiency and microstructure were also derived from structural connectome data. RESULTS: The mediation of cognition on the relationships between white matter properties and PLEs was non-significant. However, lower gFA was associated with having PLEs in combination with distress in the full available sample (standardized ß = -0.053, p = 0.011). Additionally, lower gFA/higher gMD was associated with lower g-factor (standardized ß = 0.049, p < 0.001; standardized ß = -0.027, p = 0.003), and partially mediated by processing speed with a proportion mediated of 7% (p = < 0.001) for gFA and 11% (p < 0.001) for gMD. CONCLUSIONS: We show that lower global white matter microstructure is associated with having PLEs in combination with distress, which suggests a direction of future research that could help clarify how and why individuals progress from subclinical to clinical psychotic symptoms. Furthermore, we replicated that processing speed mediates the relationship between white matter microstructure and g-factor.

The role of neuroticism in self-harm and suicidal ideation: results from two UK population-based cohorts.

BACKGROUND: Self-harm is common, debilitating and associated with completed suicide and increased all-cause mortality, but there is uncertainty about its causal risk factors, limiting risk assessment and effective management. Neuroticism is a stable personality trait associated with self-harm and suicidal ideation, and correlated with coping styles, but its value as an independent predictor of these outcomes is disputed. METHODS: Prior history of hospital-treated self-harm was obtained by record-linkage to administrative health data in Generation Scotland:Scottish Family Health Study (N = 15,798; self-harm cases = 339) and by a self-report variable in UK Biobank (N = 35,227; self-harm cases = 772). Neuroticism in both cohorts was measured using the Eysenck Personality Questionnaire-Short Form. Associations of neuroticism with self-harm were tested using multivariable regression following adjustment for age, sex, cognitive ability, educational attainment, socioeconomic deprivation, and relationship status. A subset of GS:SFHS was followed-up with suicidal ideation elicited by self-report (n = 3342, suicidal ideation cases = 158) and coping styles measured by the Coping Inventory for Stressful Situations. The relationship of neuroticism to suicidal ideation, and the role of coping style, was then investigated using multivariable logistic regression. RESULTS: Neuroticism was positively associated with hospital-associated self-harm in GS:SFHS (per EPQ-SF unit odds ratio 1.2 95% credible interval 1.1-1.2, pFDR 0.0003) and UKB (per EPQ-SF unit odds ratio 1.1 95% confidence interval 1.1-1.2, pFDR 9.8 × 10-17). Neuroticism, and the neuroticism-correlated coping style, emotion-oriented coping (EoC), were also associated with suicidal ideation in multivariable models. CONCLUSIONS: Neuroticism is an independent predictor of hospital-treated self-harm risk. Neuroticism and emotion-orientated coping styles are also predictive of suicidal ideation.

Nonlinear dynamics of solitary and optically injected two-element laser arrays with four different waveguide structures: a numerical study.

We study the nonlinear dynamics of solitary and optically injected two-element laser arrays with a range of waveguide structures. The analysis is performed with a detailed direct numerical simulation, where high-resolution dynamic maps are generated to identify regions of dynamic instability in the parameter space of interest. Our combined one- and two-parameter bifurcation analysis uncovers globally diverse dynamical regimes (steady-state, oscillation, and chaos) in the solitary laser arrays, which are greatly influenced by static design waveguiding structures, the amplitude-phase coupling factor of the electric field, i.e. the linewidth-enhancement factor, as well as the control parameter, e.g. the pump rate. When external optical injection is introduced to one element of the arrays, we show that the whole system can be either injection-locked simultaneously or display rich, different dynamics outside the locking region. The effect of optical injection is to significantly modify the nature and the regions of nonlinear dynamics from those found in the solitary case. We also show similarities and differences (asymmetry) between the oscillation amplitude of the two elements of the array in specific well-defined regions, which hold for all the waveguiding structures considered. Our findings pave the way to a better understanding of dynamic instability in large arrays of lasers.

Mapping bifurcation structure and parameter dependence in quantum dot spin-VCSELs.

We consider a modified version of the spin-flip model (SFM) that describes optically pumped quantum dot (QD) spin-polarized vertical-cavity surface-emitting lasers (VCSELs). Maps showing different dynamical regions and those consisting of various key bifurcations are constructed by direct numerical simulations and a numerical path continuation technique, respectively. A comparison between them clarifies the physical mechanism that governs the underlying dynamics as well as routes to chaos in QD spin-VCSELs. Detailed numerical simulations illustrate the role played by the capture rate from wetting layer (WL) to QD ground state, the gain parameter, and the amplitude-phase coupling. By tuning the aforementioned key parameters in turn we show how the dynamical regions evolve as a function of the intensity and polarization of the optical pump, as well as in the plane of the spin relaxation rate and linear birefringence rate, which is of importance in the design of spin lasers promising potential applications. By increasing the capture rate from WL to QD our simulation accurately describes the transition from the QD spin-VCSEL to the quantum well case, in agreement with a previous mathematical derivation, and thus validates the modified SFM equations.

Genetic risk of major depressive disorder: the moderating and mediating effects of neuroticism and psychological resilience on clinical and self-reported depression.

BACKGROUND: Polygenic risk scores (PRS) for depression correlate with depression status and chronicity, and provide causal anchors to identify depressive mechanisms. Neuroticism is phenotypically and genetically positively associated with depression, whereas psychological resilience demonstrates negative phenotypic associations. Whether increased neuroticism and reduced resilience are downstream mediators of genetic risk for depression, and whether they contribute independently to risk remains unknown. METHODS: Moderating and mediating relationships between depression PRS, neuroticism, resilience and both clinical and self-reported depression were examined in a large, population-based cohort, Generation Scotland: Scottish Family Health Study (N = 4166), using linear regression and structural equation modelling. Neuroticism and resilience were measured by the Eysenck Personality Scale Short Form Revised and the Brief Resilience Scale, respectively. RESULTS: PRS for depression was associated with increased likelihood of self-reported and clinical depression. No interaction was found between PRS and neuroticism, or between PRS and resilience. Neuroticism was associated with increased likelihood of self-reported and clinical depression, whereas resilience was associated with reduced risk. Structural equation modelling suggested the association between PRS and self-reported and clinical depression was mediated by neuroticism (43-57%), while resilience mediated the association in the opposite direction (37-40%). For both self-reported and clinical diagnoses, the genetic risk for depression was independently mediated by neuroticism and resilience. CONCLUSIONS: Findings suggest polygenic risk for depression increases vulnerability for self-reported and clinical depression through independent effects on increased neuroticism and reduced psychological resilience. In addition, two partially independent mechanisms - neuroticism and resilience - may form part of the pathway of vulnerability to depression.

Genome-wide association study of alcohol consumption and genetic overlap with other health-related traits in UK Biobank (N=112 117).

Alcohol consumption has been linked to over 200 diseases and is responsible for over 5% of the global disease burden. Well-known genetic variants in alcohol metabolizing genes, for example, ALDH2 and ADH1B, are strongly associated with alcohol consumption but have limited impact in European populations where they are found at low frequency. We performed a genome-wide association study (GWAS) of self-reported alcohol consumption in 112 117 individuals in the UK Biobank (UKB) sample of white British individuals. We report significant genome-wide associations at 14 loci. These include single-nucleotide polymorphisms (SNPs) in alcohol metabolizing genes (ADH1B/ADH1C/ADH5) and two loci in KLB, a gene recently associated with alcohol consumption. We also identify SNPs at novel loci including GCKR, CADM2 and FAM69C. Gene-based analyses found significant associations with genes implicated in the neurobiology of substance use (DRD2, PDE4B). GCTA analyses found a significant SNP-based heritability of self-reported alcohol consumption of 13% (se=0.01). Sex-specific analyses found largely overlapping GWAS loci and the genetic correlation (rG) between male and female alcohol consumption was 0.90 (s.e.=0.09, P-value=7.16 × 10-23). Using LD score regression, genetic overlap was found between alcohol consumption and years of schooling (rG=0.18, s.e.=0.03), high-density lipoprotein cholesterol (rG=0.28, s.e.=0.05), smoking (rG=0.40, s.e.=0.06) and various anthropometric traits (for example, overweight, rG=-0.19, s.e.=0.05). This study replicates the association between alcohol consumption and alcohol metabolizing genes and KLB, and identifies novel gene associations that should be the focus of future studies investigating the neurobiology of alcohol consumption.

Compression socks and the effects on coagulation and fibrinolytic activation during marathon running.

PURPOSE: Compression socks are frequently used in the treatment and prevention of lower-limb pathologies; however, when combined with endurance-based exercise, the impact of compression socks on haemostatic activation remains unclear. OBJECTIVES: To investigate the effect of wearing compression socks on coagulation and fibrinolysis following a marathon. METHODS: Sixty-seven participants [43 males (mean ± SD: age: 46.7 ± 10.3 year) and 24 females (age: 40.0 ± 11.0 year)] were allocated into a compression (SOCK, n = 34) or control (CONTROL, n = 33) group. Venous blood samples were obtained 24 h prior to and immediately POST-marathon, and were analyzed for thrombin-anti-thrombin complex (TAT), tissue factor (TF), tissue factor pathway inhibitor (TFPI), and D-Dimer. RESULTS: Compression significantly attenuated the post-exercise increase in D-Dimer compared to the control group [median (range) SOCK: + 9.02 (- 0.34 to 60.7) ng/mL, CONTROL: + 25.48 (0.95-73.24) ng/mL]. TF increased following the marathon run [median (range), SOCK: + 1.19 (- 7.47 to 9.11) pg/mL, CONTROL: + 3.47 (- 5.01 to 38.56) pg/mL] in all runners. No significant post-exercise changes were observed for TAT and TFPI. CONCLUSIONS: While activation of coagulation and fibrinolysis was apparent in all runners POST-marathon, wearing compression socks was shown to reduce fibrinolytic activity, as demonstrated by lower D-Dimer concentrations. Compression may reduce exercise-associated haemostatic activation when completing prolonged exercise.

Secure communication systems based on chaos in optically pumped spin-VCSELs.

We report on a master and slave configuration consisting of two optically pumped spin-vertical-cavity surface-emitting lasers for chaos synchronization and secure communication. Under appropriate conditions, high-quality chaos synchronization is achieved. We propose two encryption schemes, where either the pump magnitude or polarization is modulated. The results show that these allow for Gb/s transmission of secure data, but exhibit different features: one indicates that the message can be recovered by the total intensity, but not the polarization components, whereas the other shows that the message can be better or exclusively retrieved from the polarization components at high bit rates.

High frequency continuous birefringence-induced oscillations in spin-polarized vertical-cavity surface-emitting lasers.

Sustained, large amplitude and tunable birefringence-induced oscillations are obtained in a spin-vertical cavity surface-emitting laser (spin-VCSEL). Experimental evidence is provided using a spin-VCSEL operating at 1300 nm, under continuous-wave optical pumping and at room temperature. Numerical and stability analyses are performed to interpret the experiments and to identify the combined effects of pump ellipticity, spin relaxation rate, and cavity birefringence. Importantly, the frequency of the induced oscillations is determined by the device's birefringence rate, which can be tuned to very large values. This opens the path for ultrafast spin-lasers operating at record frequencies exceeding those possible in traditional semiconductor lasers and with ample expected impact in disparate disciplines (e.g., datacomms, spectroscopy).

Tracking the changes in virus taxonomy.

A database and website ( http://www.ictvonline.org/taxonomyReleases.asp ) have been established where the history of changes in virus taxonomy from 1971 to the present day can easily be traced. Each change is linked to a source document confirming the change or, for most changes since 2002, to the taxonomic proposal approved by the International Committee on Taxonomy of Viruses (ICTV).

Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses (2015).

Changes to virus taxonomy approved and ratified by the International Committee on Taxonomy of Viruses in February 2015 are listed.

Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses (2014).

Changes to virus taxonomy approved by a vote of all ICTV members in February-March 2014 are reported.

Chytrid infections exhibit historical spread and contemporary seasonality in a declining stream-breeding frog.

Species with extensive geographical ranges pose special challenges to assessing drivers of wildlife disease, necessitating collaborative and large-scale analyses. The imperilled foothill yellow-legged frog (Rana boylii) inhabits a wide geographical range and variable conditions in rivers of California and Oregon (USA), and is considered threatened by the pathogen Batrachochytrium dendrobatidis (Bd). To assess drivers of Bd infections over time and space, we compiled over 2000 datapoints from R. boylii museum specimens (collected 1897-2005) and field samples (2005-2021) spanning 9° of latitude. We observed a south-to-north spread of Bd detections beginning in the 1940s and increase in prevalence from the 1940s to 1970s, coinciding with extirpation from southern latitudes. We detected eight high-prevalence geographical clusters through time that span the species' geographical range. Field-sampled male R. boylii exhibited the highest prevalence, and juveniles sampled in autumn exhibited the highest loads. Bd infection risk was highest in lower elevation rain-dominated watersheds, and with cool temperatures and low stream-flow conditions at the end of the dry season. Through a holistic assessment of relationships between infection risk, geographical context and time, we identify the locations and time periods where Bd mitigation and monitoring will be critical for conservation of this imperilled species.

Selection pressure and founder effects constrain genetic variation in differentiated populations of soilborne bymovirus Wheat yellow mosaic virus (Potyviridae) in China.

To study the population genetic structure and forces driving the evolution of Wheat yellow mosaic virus (WYMV), the nucleotide sequences encoding the coat protein (CP) (297 sequences) or the genome-linked virion protein (VPg) (87 sequences) were determined from wheat plants growing at 11 different locations distributed in five provinces in China. There were close phylogenetic relationships between all sequences but clustering on the phylogenetic trees was congruent with their provenance, suggesting an origin-dependent population genetic structure. There were low levels of genetic diversity, ranging from 0.00035 ± 0.00019 to 0.01536 ± 0.00043 (CP), and 0.00086 ± 0.00039 to 0.00573 ± 0.00111 (VPg), indicating genetic stability or recent emergence of WYMV in China. The results may suggest that founder effects play a role in shaping the genetic structure of WYMV. Between-population diversity was consistently higher than within-population diversity, suggesting limited gene flow between subpopulations (average FST 0.6241 for the CP and 0.7981 for the VPg). Consistent amino acid substitutions correlated with the provenance of the sequences were observed at nine positions in the CP (but none in the VPg), indicating an advanced stage in population structuring. Strong negative (purifying) selection was implicated on both the CP and VPg but positive selection on a few codons in the CP, indicating an ongoing molecular adaptation.

Risk of cardiovascular disease in HIV, hepatitis C, or HIV/hepatitis C patients compared to the general population.

BACKGROUND: As a result of effective antiretroviral therapy HIV patients are living longer, and their risk of cardiovascular disease (CVD) is a growing concern. It remains unknown whether coinfection with hepatitis C (HCV) changes an HIV person's CVD risk, and how the risks compare to the general population. The objective of this study was to compare the Framingham Risk Score (FRS) and vascular age differences in persons with HIV, HCV or HIV/HCV disease to the general population. METHODS: HIV, HCV, and HIV/HCV patients with clinic visits between 2004 and 2009 were sampled from medical clinics in Rochester, NY. Uninfected persons were randomly selected from the National Health and Nutrition Examination Survey (NHANES), and individually matched on gender, race, and age. We stratified by infection group and conducted separate multivariable linear regression analyses between each infection group and the gender, race, and age matched participants from NHANES. RESULTS: Rochester patients (HIV = 239, HCV = 167, HIV/HCV = 182) were compared 3 : 1 with the NHANES participants. After controlling for weight, marital status, current pharmacotherapies and the matching variables of gender, race, and age, HIV/HCV patients had a 2% higher general FRS compared with the general population (p = 0.03), and vascular age differences that were 4.1 years greater (p = .01). HCV patients had a 2.4% higher general FRS than the general population (p < .001), and vascular age differences that were 4.4 years greater (p < .001). CVD risk was elevated but not significantly different between HIV patients and the general population. CONCLUSION: Cardiovascular disease risk is elevated among HIV/HCV and HCV infected persons compared with the general population.

Polygenic prediction of major depressive disorder and related traits in African ancestries UK Biobank participants.

Introduction: Genome-Wide Association Studies (GWAS) over-represent European ancestries compared to the global population, neglecting all other ancestry groups and low-income nations. Consequently, polygenic risk scores (PRS) more accurately predict complex traits in Europeans than African Ancestries groups. Very few studies have looked at the transferability of European-derived PRS for behavioural and mental health phenotypes to non-Europeans. We assessed the comparative accuracy of PRS for Major Depressive Disorder (MDD) trained on European and African Ancestries GWAS studies to predict MDD and related traits in African Ancestries participants from the UK Biobank. Methods: UK Biobank participants were selected based on Principal component analysis (PCA) clustering with an African genetic similarity reference population and MDD was assessed with the Composite International Diagnostic Interview (CIDI). Polygenic Risk Scores (PRS) were computed using PRSice2 using either European or African Ancestries GWAS summary statistics. Results: PRS trained on European ancestry samples (246,363 cases) predicted case control status in Africans of the UK Biobank with similar accuracies (190 cases, R2=2%) to PRS trained on far much smaller samples of African Ancestries participants from 23andMe, Inc. (5045 cases, R2=1.8%). This suggests that prediction of MDD status from Africans to Africans had greater efficiency per unit increase in the discovery sample size than prediction of MDD from Europeans to Africans. Prediction of MDD status in African UK Biobank participants using GWAS findings of causal risk factors from European ancestries was non-significant. Conclusion: GWAS studies of MDD in European ancestries are an inefficient means of improving polygenic prediction accuracy in African samples.

Stability of the nonlinear dynamics of an optically injected VCSEL.

Automated protocols have been developed to characterize time series data in terms of stability. These techniques are applied to the output power time series of an optically injected vertical cavity surface emitting laser (VCSEL) subject to varying injection strength and optical frequency detuning between master and slave lasers. Dynamic maps, generated from high resolution, computer controlled experiments, identify regions of dynamic instability in the parameter space.

IgG fractions from patients with antiphospholipid syndrome and systemic lupus erythematosus bind to platelets, but do not affect collagen-induced platelet activation.

Anti-beta-2 glycoprotein 1 (anti-ß2GP1) is an antiphospholipid antibody found in patients with antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). Its presence commonly is associated with thrombosis; however, the mechanisms of interaction of anti-ß2GP1 antibodies and platelets remain unclear. We investigated the effects of APS and SLE patient-derived IgG fractions on collagen-mediated platelet aggregation and examined the binding of patient-derived IgG to platelets before and after activation by collagen. IgG fractions, 150, 200, 300 or 350 µg/ml, isolated from 11 patients with APS and SLE were incubated with two sets of platelet-rich plasma (PRP) in the incubation wells of an aggregometer. The first set was activated by collagen and the other set was incubated for an additional 10 min. All platelets were collected by centrifugation and fixed in cell blocks. We assessed binding of IgG to platelets using immunocytochemistry (ICC). Patient-derived IgG fractions did not affect collagen-induced platelet aggregation. ICC staining using anti-human IgG antibodies demonstrated that patient-derived IgG fractions had greater affinity for non-activated platelets than those activated by 0.75 µg/ml collagen. Patient-derived IgG fractions bound to the surface of platelets and potentially could be internalized by platelets. IgG fractions from APS and SLE patients may sensitize non-activated platelets, which could increase platelet reactivity and thrombotic risk in patients. We did not detect secondary effects of patient-derived IgG fractions.

Indirect genetics effects and evolutionary constraint: an analysis of social dominance in red deer, Cervus elaphus.

By determining access to limited resources, social dominance is often an important determinant of fitness. Thus, if heritable, standard theory predicts mean dominance should evolve. However, dominance is usually inferred from the tendency to win contests, and given one winner and one loser in any dyadic contest, the mean proportion won will always equal 0.5. Here, we argue that the apparent conflict between quantitative genetic theory and common sense is resolved by recognition of indirect genetic effects (IGEs). We estimate selection on, and genetic (co)variance structures for, social dominance, in a wild population of red deer Cervus elaphus, on the Scottish island of Rum. While dominance is heritable and positively correlated with lifetime fitness, contest outcomes depend as much on the genes carried by an opponent as on the genotype of a focal individual. We show how this dependency imposes an absolute evolutionary constraint on the phenotypic mean, thus reconciling theoretical predictions with common sense. More generally, we argue that IGEs likely provide a widespread but poorly recognized source of evolutionary constraint for traits influenced by competition.

Impaired control of the tissue factor pathway of blood coagulation in systemic lupus erythematosus.

Thrombosis is a frequent manifestation in patients with systemic lupus erythematosus (SLE), although precise mechanisms remain unclear. This study investigated whether the major physiological trigger of blood coagulation, the tissue factor (TF) pathway, was altered in SLE patients. Furthermore, we investigated potential associations between the TF pathway, the presence of antiphospholipid (APL) antibodies and other abnormalities present in SLE. A total of 101 participants (40 SLE patients and 61 age- and sex-matched controls) were recruited from Tasmania, Australia. Markers of the TF pathway, hypercoagulability, inflammation and endothelial cell damage were measured in plasma. Serum levels of APL antibodies (anti-cardiolipin antibodies [ACL], lupus anticoagulants [LAC], anti-beta2-glycoprotein-1 [anti-ß2GP1] and anti-prothrombin antibodies) were also determined. Despite similar TF and TF pathway inhibitor (TFPI) total antigen levels, SLE patients had significantly increased levels of TFPI free antigen (patients vs controls; mean ± SD) (11.6 ± 0.9 ng/mL vs 6.4 ± 0.4 ng/mL; p < 0.001) but significantly reduced TFPI activity (0.66 ± 0.07 U/mL vs 1.22 ± 0.03 U/mL; p < 0.001), compared with healthy controls. Anti-TFPI activity, designated as the ability of isolated IgG fractions to inhibit TFPI activity in normal plasma, was detected in 19/40 (47.5%) of SLE patients and 3/40 (7.5%) of healthy controls. The significant reduction in TFPI activity in SLE patients reflects impaired functional control of the TF pathway. Moreover, SLE patients with a history of thrombosis demonstrated higher levels of TFPI activity compared with patients without a previous thrombotic event (0.97 ± 0.07 U/mL vs 0.53 ± 0.14 U/mL; p = 0.0026). Changes to the TF pathway were not associated with manifestations of SLE such as inflammation or endothelial cell damage. The results from this study suggest hypercoagulability in SLE may (in part) be due to reduced TFPI activity, a mechanism that appears to be independent of other abnormalities in SLE.